This invention relates to stone cutting devices in general, and in particular to such a device having a flexible and continuous stone cutting belt.
Various means have been developed over the years for cutting and removing hard natural stone from quarries. In U.S. Pat. No. 3,884,212, I disclosed an improved wire saw that is adaptable for cutting stone which is still in the ground. This wire saw includes abrasive cutting elements sleeved over an endless flexible wire, and a pressure molded-in-place resilient material surrounding the cable and providing a substantially uniform diameter for the endless saw.
In another method for removing stone from the ground, it is known to drill holes in stone and then wedge large pieces of stone out with mechanical means employing hydraulics and pneumatics. This method is difficult, time consuming, and does not result in a smooth, cut surface on the stone. A device known to be used in Europe includes a jib pivotally mounted to a vehicle having aligned sprockets and a guidebar to drive a continuous chain on which diamond cutting bits are attached for cutting stone. The jib travels through the stone as it is cut away by the chainsaw. Several problems are associated with using this chain-type saw. The chain is heavy, expensive, and must be run a slow speeds because of its mechanical construction. The chain also causes vibration, or chatter, during operation and wears out easily. Should the chain break during operation, it may perilously fly off the jib.
In U.S. Pat. No. 4,603,678, I disclosed an improved belt-configured saw for cutting a slot in stone, comprising a mainframe, a jib movable mounted to the mainframe, and a continuous flexible belt extending around and in driven engagement with sheaves on the jib. The belt includes a plurality of spaced apart abrasive cutting strips extending across the top and sides of the belt. This belt-configured saw employs a grinding action rather than a cutting action to remove the stone. Since this belt-configured device operates by a grinding action, greater energy is required to drive the belt than would ordinarily be required for a device operating by a cutting action. In addition, the grinding action of this type of belt-configured saw requires higher belt tension so that the abrasive cutting strips can be fully operative. Moreover, the abrasive cutting strips, produced from a powdered metal mix, such as bronze having diamonds positioned uniformly throughout, are expensive and difficult to produce.